TW202413384A - High purity liquid composition and uses of the same - Google Patents

Abstract

A pure composition comprises a monoalkyltin trialkoxide compound represented by the chemical formula RSn(OR’) ₃or a monoalkyl tin triamide compound represented by the chemical formula RSn(NR’ ₂) ₃and no more than 4 mole% dialkyltin compounds relative to the total tin amount, where R is a hydrocarbyl group with 1-31 carbon atoms, and wherein R’ is a hydrocarbyl group with 1-10 carbon atoms. Methods are described for the formation of the pure compositions. A solid composition comprises a monoalkyl triamido tin compound represented by the chemical formula RSn-(NR'COR") ₃, where R is a hydrocarbyl group with 1-31 carbon atoms, and where R’ and R" are independently a hydrocarbyl group with 1-10 carbon atoms. The compositions are suitable for the formation of resist compositions suitable for EUV patterning in which the compositions have a high EUV absorption.

Description

High purity liquid composition and its application

The present invention relates to a high purity composition of monoalkyl tin triamide, monoalkyl tin trialkoxide or monoalkyl triamido tin and a preparation method thereof.

Organometallic compounds are advantageous for providing metal ions in a solution processable form. Alkyltin compounds provide radiation sensitive Sn-C bonds that can be used for photolithographic patterning structures. Processing of semiconductor materials with ever-shrinking dimensions has resulted in the need for more versatile materials to achieve the desired patterning resolution, and alkyltin compounds are promising advanced materials to provide patterning advantages.

In a first aspect, the present invention relates to a composition comprising a monoalkyltin trialkoxide represented by the chemical formula RSn(OR') ₃ , or a monoalkyltin triamine compound represented by the chemical formula RSn(NR' ₂ ) ₃ , and no more than 4 mol% of a dialkyltin compound based on the total tin content, wherein R is a alkyl group having 1 to 31 carbon atoms, and wherein R' is a alkyl group having 1 to 10 carbon atoms. The monoalkyltin triamine can be reacted with an alcohol represented by the formula HOR" in an organic solvent to form RSn(OR") ₃ , wherein R" is each independently a alkyl group having 1 to 10 carbon atoms, thereby forming a product composition, wherein the product composition has no more than 4 mol% of a dialkyltin compound based on the total tin content.

In another aspect, the present invention relates to a composition comprising a monoalkyl triamide tin compound represented by RSn-(NR'COR") ₃ , wherein R is a alkyl group having 1 to 31 carbon atoms, and wherein R' and R" are each independently a alkyl group having 1 to 10 carbon atoms.

In another embodiment, the present invention relates to a method for forming a monoalkyltintriamine compound, the method comprising: reacting an alkylating agent with Sn(NR' ₂ ) ₄ in a solution containing an organic solvent, wherein the alkylating agent is selected from the group consisting of RMgX, R ₂ Zn, RZnNR' ₂ , or a combination thereof, wherein R is a alkyl group having 1 to 31 carbon atoms, wherein X is a halogen, and wherein R' is a alkyl group having 1 to 10 carbon atoms.

In other aspects, the present invention relates to a method for selectively forming a monoalkyltin trialkoxide having low dialkyltin contaminants, the method comprising: reacting RSn(NR' ₂ ) ₃ with an alcohol represented by the formula HOR" in an organic solvent to form RSn(OR") ₃ , wherein the RSn(NR' ₂ ) ₃ reactant has no more than about 4 mol % of dialkyltin contaminants and is the product of the method as described in claim 17, wherein R is a alkyl group having 1 to 31 carbon atoms, and wherein R' and R" are each independently a alkyl group having 1 to 10 carbon atoms.

In another embodiment, the present invention relates to a method for forming a monoalkyltriamide tin, the method comprising: reacting a monoalkyltintriamine compound represented by the chemical formula RSn( _NR'2 ) ₃ with an amide (R"CONHR"') in an organic solvent, wherein R is a alkyl group having 1 to 31 carbon atoms, and wherein R', R" and R"' are each independently a alkyl group having 1 to 8 carbon atoms; and collecting a solid product represented by the formula RSn(NR"'COR") ₃ .

In addition, the present invention relates to a method for forming a monoalkyltin trialkoxide, which comprises: reacting a monoalkyltriamidotin compound (RSn(NR"'COR") ₃ ) with an alkali metal alkoxide (QOR', wherein Q is an alkali metal atom) in an organic solvent to form a product compound represented by the chemical formula RSn(OR') ₃ , wherein R is a alkyl group having 1 to 31 carbon atoms, and wherein R', R" and R'" are each independently a alkyl group having 1 to 10 carbon atoms.

Furthermore, the present invention relates to a method for purifying monoalkyl tin trialkoxide, comprising distilling a blend of monoalkyl tin trialkoxide and a tetradentate non-planar complexing agent.

Methods have been found to obtain monoalkyltin compositions, particularly monoalkyltin triamines, monoalkyltin trialkoxides and monoalkyltin triamides, having low polyalkyltin byproducts. In particular, three methods have been developed for synthesizing monoalkyltin triamines having relatively low polyalkyltin byproducts, which byproducts can be used as synthesized or further purified. The selectively synthesized monoalkyltin triamines can then be used to synthesize monoalkyltin trialkoxides having correspondingly low polyalkyltin byproducts. Furthermore, the monoalkyltin triamines, whether pure or not, can be reacted in solution to form solid monoalkyltin triamides, the crystals of which do not include polyalkyl byproducts, so that the methods have been found to be effective for forming monoalkyltin triamides having low polyalkyl byproducts. The synthesized monoalkyltin amines and monoalkyltin alkoxides can be further purified by fractionation to effectively reduce polyalkyl contaminants to levels lower than the relatively low levels in the direct synthesis. Analytical techniques can be used to assess the contaminant content. In some embodiments, quantitative NMR (qNMR) shows that the byproducts can be reduced to concentrations below 1 mol%. The tin product composition is beneficial for use as a precursor for synthesizing desired patterning materials. For applications as a precursor for patterning materials, the reduction of polyalkyltin byproducts is beneficial to the properties of the monoalkyltin product composition for use as EUV and UV photoresists or electron beam patterning resists.

Monoalkyltin triamines can be useful intermediates in the preparation of organotin photoresists. The methods for preparing monoalkyltin triamines have previously used lithium reagents to convert tin tetraamide to the desired triamine. For example, tertiary butyl tris(diethylamino)tin (t-BuSn(NEt ₂ ) ₃ ) can be synthesized using lithium reagents according to Hänssgen, D.; Puff, H.; Beckerman, N. ‎J., Organomet. Chem. 1985, 293, 191, which is incorporated herein by reference in its entirety. However, these methods using lithium reagents produce a mixture of monoalkyl and dialkyltin products. Moreover, lithium contamination is undesirable for semiconductor applications. The disclosed method for preparing monoalkyltin triamines containing dialkyl groups produces a mixture rich in monoalkyltin, dialkyltin, and trialkyltin products. As explained below, it is desirable to reduce any polyalkyl byproducts, such as dialkyltin contaminants. Although for certain compounds, the monoalkyl and dialkyl species can be separated from each other, the separation or purification process generally increases manufacturing costs, and the entrained dialkyl impurities may impair the performance of downstream photoresist products. Therefore, it is desirable to synthesize monoalkyltin compounds with higher purity so that any subsequent purification, such as using fractionation if necessary, can result in even lower dialkyl or polyalkyl contamination. If the composition after synthesis as described above is sufficiently pure, further purification by fractionation can be avoided.

The use of high purity monoalkyltin compounds, particularly alkyl compounds, as polymer stabilizers is described in U.S. Patent Nos. 8,198,352 to Deelman et al., entitled "High Purity Monoalkyltin Compounds and Uses Thereof," and 9,745,450 to Frenkel et al., entitled "Stabilizers Containing High Purity Mono-Alkyltin Compounds," both of which are incorporated herein by reference in their entirety. These patents describe the formation of pure monoalkyl halides as precursors for the synthesis of stabilizer compounds. The methods described herein focus on the synthesis of high purity monoalkyltin triamines, monoalkyltin trialkoxides or monoalkyltriamide tin compounds using different and efficient synthetic methods, which can be used for purification together with distillation.

For example, U.S. Patent No. 9,310,684 to Meyers et al., entitled “Organometallic Solution Based High Resolution Patterning Compositions,” describes the use of alkyl metal coordination compounds in high performance radiation based patterning compositions, which is incorporated herein by reference in its entirety. Improvements in these organometallic compositions for patterning are described in U.S. Patent Application No. 2016/0116839 A1 to Meyers et al., entitled “Organometallic Solution Based High Resolution Patterning Compositions and Corresponding Methods,” and U.S. Published Patent Application No. 2017/0102612 A1 to Meyers et al., entitled “Organotin Oxide Hydroxide Patterning Compositions, Precursors, and Patterning” (hereinafter referred to as the '612 case), both of which are incorporated herein by reference in their entirety.

Radiation patterning with alkyltin compositions is typically performed with alkyltin oxo-hydroxy moieties. The compositions synthesized herein can be effective precursors to form alkyltin oxo-hydroxy compositions that are effective for high resolution patterning. The alkyltin precursor composition comprises a group that can be hydrolyzed with water or other suitable reagents under appropriate conditions to form an alkyltin oxo-hydroxy patterning composition that can be represented by the formula RSnO _(1.5-(x/2)) (OH) _x , wherein 0 < x ≤ 3. Hydrolysis and condensation reactions that can transform compositions with hydrolyzable groups (X) are shown in the following reactions: _RSnX3 + 3 _H2O → RSn(OH) ₃ + 3 HX, RSn(OH) ₃ → RSnO _{(1.5-(x/2)) OHx} + (x/2) _H2O If the hydrolysis product HX is sufficiently volatile, it can be hydrolyzed in situ with water vapor during the substrate coating process, but the hydrolysis reaction can also be carried out in solution to form an alkyltinoxide-hydroxy composition. These processing options are further described in the '612 case.

Polyalkyltin dopant compositions may affect condensation and cause outgassing of photoresists during photolithographic processing, which increases the potential for tin contamination of equipment used for film deposition and patterning. Based on these concerns, there is a strong need to reduce or eliminate dialkyl or other polyalkyl components. Three types of compositions are relevant to the processing described herein for reducing polyalkyltin contaminants in the final photoresist composition, which is specifically monoalkyltin triamines, monoalkyltin trialkoxides, and monoalkyltin triamides. As further explained below, monoalkyltin triamine compositions can also be used as precursors for monoalkyltin trialkoxides and monoalkyltin triamides. Monoalkyltriamidotin compositions can also be suitable precursors for forming monoalkyltin trialkoxide compositions. Monoalkyltin trialkoxide compositions can be desirable components in the precursor patterning composition solution because they can be hydrolyzed and condensed in situ with alcohol byproducts to form monoalkyltin oxide-hydroxy compositions, wherein the alcohol byproducts are generally sufficiently volatile to be removed by in situ hydrolysis.

Monoalkyltintriamine compositions with relatively low polyalkyl contaminants can be directly synthesized using any of the three methods described herein. The method with Zn reagent is specifically used to synthesize pure monoalkyltintriamines containing dialkyl groups. In addition, at least some of the monoalkyltintriamine compositions can be further purified using distillation. The synthesis of monoalkyltriamidetin compositions from monoalkyltintriamine compositions provides another method to reduce polyalkyl contaminants. The methods can be combined to further reduce polyalkyl contaminants.

The monoalkyltin triamine composition can be generally represented by the formula RSn(NR') ₃ , wherein R and R' are each independently an alkyl or cycloalkyl group having 1 to 31 carbon atoms, wherein one or more carbon atoms are optionally substituted with one or more heteroatom functional groups containing O, N, Si and/or halogen atoms, or the alkyl or cycloalkyl group is further functionalized with a phenyl or cyano group. In some embodiments, R' may contain ≤10 carbon atoms and may be, for example, methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl, isobutyl or tertiary amyl. The R group may be a straight chain, a branched chain (i.e., a secondary or tertiary on the metal-bonded carbon atom), or a cyclic hydrocarbon group. Each R group is independently and generally has 1 to 31 carbon atoms, of which 3 to 31 carbon atoms are secondary-bonded and 4 to 31 carbon atoms are tertiary-bonded. In particular, for some patterned compositions, branched alkyl ligands may be desirable, wherein the compound may be represented as R ¹ R ² R ³ CSn(NR') ₃ , wherein R ¹ and R ² are independently alkyl groups having 1 to 10 carbon atoms, and R ³ is hydrogen or an alkyl group having 1 to 10 carbon atoms. As described below, this representation of the alkyl ligand R is similarly applicable to other embodiments generally having R ¹ R ² R ³ CSn(X) ₃ , wherein X corresponds to a trialkoxy or triamine moiety. In some embodiments, ^R1 and ^R2 may form a cyclic alkyl moiety, and ^R3 may also be linked to other groups in the cyclic moiety. Suitable branched alkyl ligands may be, for example, isopropyl ( ^R1 and ^R2 are methyl, ^R3 is hydrogen), tertiary butyl ( ^R1 , ^R2 and ^R3 are methyl), tertiary pentyl ( ^R1 and ^R2 are methyl, ^R3 is _-CH2CH3 ), dibutyl ( ^R1 is methyl, ^R2 is _{-CH2CH3 ,} ^R3 is hydrogen), neopentyl ( ^R1 and ^R2 are hydrogen, ^R3 is -C( _CH3 ) ₃ ), cyclohexyl _, cyclopentyl, cyclobutyl and cyclopropyl. Examples of suitable cyclic groups include, for example, 1-adamantyl (-C(CH ₂ ) ₃ (CH) ₃ (CH ₂ ) ₃ , tricyclo(3.3.1.13,7)decane bonded to the metal with a tertiary carbon), and 2-adamantyl (-CH(CH) ₂ (CH ₂ ) ₄ (CH) ₂ (CH ₂ ), tricyclo(3.3.1.13,7)decane bonded to the metal with a secondary carbon). In other embodiments, the alkyl group may include an aryl or alkenyl group, such as a benzyl or allyl group, or an alkynyl group. In other embodiments, the alkyl ligand R may include any group consisting only of C and H and containing 1 to 31 carbon atoms. For example: straight chain or branched chain alkyl (i-Pr ((CH ₃ ) ₂ CH-), t-Bu ((CH ₃ ) ₃ C-), Me (CH ₃ -), n-Bu (CH ₃ CH ₂ CH ₂ CH ₂ -)), cycloalkyl (cyclopropyl, cyclobutyl, cyclopentyl), alkenyl (alkenyl, aryl, allyl), or alkynyl, or a combination thereof. In a further embodiment, suitable R groups may include alkyl groups substituted with heteroatom functional groups, wherein the heteroatom functional groups include cyano, thio, silyl, ether, keto, ester or halogenated groups or a combination thereof.

The alkyltin trialkoxide composition can be represented by the formula RSn(OR ⁰ ) ₃ , and the alkyltriamide tin composition can be represented by the formula RSn(NR"COR"') _3. The R groups in the general formulas of the alkyltin trialkoxide and alkyltriamide tin compositions can be the same R groups as summarized above for the alkyltintriamine compositions, and the corresponding discussion of these R groups is replicated in this paragraph in its entirety. For the alkylamide group (-NR"COR"') or the alkoxy ligand -OR ⁰ , the R", R"' and R ⁰ groups can each independently be a alkyl group having 1 to 10 carbon atoms, such as methyl, ethyl, etc. R" and R"' can also each independently be hydrogen.

In some embodiments, the compositions herein (monoalkyltin triamine, monoalkyltin trialkoxide, or monoalkyltin triamide) may have no more than about 4 mole % of dialkyltin contaminants relative to tin, no more than about 3 mole % in other embodiments, no more than about 2 mole %, in other embodiments, no more than about 1 mole % of dialkyltin contaminants, in other embodiments, no more than about 0.5 mole % of dialkyltin contaminants, and in another embodiment, no more than about 0.1 mole %. Those of ordinary skill in the art will recognize that other ranges of dialkyltin contaminants within the above explicit ranges are contemplated and within the scope of the present disclosure. The content of dialkyltin contaminants can generally be determined using any reasonable analytical technique. In some embodiments, the amount of dialkyltin diamine or dialkyltin dialkoxide can be shown by quantitative NMR to be close to or below 0.1 mol%. Due to potential unidentified contaminants, the quantification of the monoalkyltin composition can be measured within a few percentage points, but the use of quantitative NMR as described in the following examples provides reliability for the error level of relatively small amounts of dialkyltin contaminants.

The derivatized monoalkyl Sn precursors were analyzed by ¹ H and ¹¹⁹ Sn NMR spectroscopy. Purity was determined using the integration of the NMR spectral peaks from the monoalkyl Sn precursors relative to an internal standard. Precautions were taken to ensure that these values accurately reflected the purity of the monoalkyl Sn precursors. A calibrated 90 degree pulse was used to irradiate the samples for ¹ H NMR and inverse-gated ¹¹⁹ Sn { ¹ H} NMR experiments. In addition, for both ¹ H and ¹¹⁹ Sn { ¹ H} NMR experiments, T ₁ relaxation values of the standards and analytes were measured using inversion recovery experiments. The measured _T1 value was used to set the recycle delay time equal to 5 times the longest _T1 time of the sample, allowing the nucleus to return from almost complete relaxation (Z = 1 – e- ^{( elapsed time /T1)} ) to equilibrium (Z = 1 – e ^-5 = 0.99326). Finally, for the ¹¹⁹ Sn{ ¹ H} NMR experiments, the B1 curve of the NMR spectrometer was measured and interpreted centered between the analyte and standard spectra in order to reduce the intensity of peaks not in the center of the spectral window. Detection and quantification of trace Sn impurities were accomplished using a parameter set for inversion-gated ¹¹⁹ Sn{ ¹ H} NMR spectra to enhance the signal-to-noise ratio in the spectra: the center and sweep width of the spectra were set to calibration values, a 30 degree pulse was used to irradiate the sample, and the cycle delay time was set to 1 second. Linear regression analysis was used to assign quantitative values to the low-level Sn impurities detected. The method provided quantification limits of 0.1% for dialkyl, tetraalkylamine, and tetraalkoxytin impurities relative to monoalkyltin compounds. Quantitative NMR is further described in Weber et al., “Method development in quantitative NMR towards metrologically traceable organic certified reference materials used as ³¹ P qNMR standards”, Anal. Bioanal. Chem., 407:3115-3123 (2015) and Pauli et al., “Importance of Purity Evaluation and the Potential of Quantitative ^{1 H} NMR as a Purity Determination”, J. Medicinal Chemistry, 57, 9220-9231 (2014). Quantitative ¹ H NMR as a Purity Assay). The entire texts of these two documents are incorporated herein by reference.

Generally, the improved method for preparing monoalkyltintriamines herein comprises reacting a compound having an alkyl donating group (also referred to as an alkylating agent) with tintetramine. Desired results have been achieved, wherein the alkylating agent can be a grignard reagent, a diorganic zinc reagent, or a monoorganic zinc amine. These syntheses can directly produce monoalkyltintriamines with low polyalkyl contaminants, which can be used to form photoresists or can be further purified to further reduce the contaminant content. In the synthetic method, the alkylating agent selectively replaces the amine group of tintetramine with an alkyl group. In some embodiments, the reaction selectively produces monoalkyltintriamines with low polyalkyltin contaminants (particularly low dialkyltin contaminants). The synthetic methods described improve the selectivity and yield of monoalkyltin triamines by limiting the formation of dialkyltin byproducts. The methods are particularly applicable to branched alkyl systems. The monoalkyltin triamines with low polyalkyl contaminants can then be used to form monoalkyltin trialkoxides with low polyalkyl contaminants. As discussed further below, the formation of crystalline monoalkyltriamide-based tin compositions provides another method to avoid polyalkyl contaminants by excluding such contaminants from the crystal.

For the reaction to form the monoalkyltin triamine compound, the tin tetramine compound can be obtained commercially or synthesized using known techniques. For example, tetrakis(dimethylamino)tin (Sn(NMe ₂ ) ₄ ) can be purchased from Sigma-Aldrich. For the synthesis of the monoalkyltin composition, the tin tetramine reactant in the solution can generally have a concentration of about 0.01 M to about 5 M, particularly about 0.025 M to about 5 M, in further embodiments, about 0.05 M to about 4 M, or in other embodiments, about 0.1 M to about 2 M. Those of ordinary skill in the art will recognize that additional ranges of reactant concentrations within the above explicit ranges are contemplated and within the scope of the present disclosure. Typically, the relevant reaction of introducing alkyl ligands into Sn can be initiated in solution with tin tetramine in a reactor under an inert gas purge and in the dark. In another embodiment, some or all of the tin tetramine reactant is added gradually, in which case the above concentrations may not be directly relevant because higher concentrations may be appropriate in the gradually added solution and the concentration in the reactor may be transient.

The alkylating agent is typically added in an amount that is relatively close to the stoichiometric amount. In other words, the alkylating agent is added to provide one molar equivalent of alkyl group for one Sn atom. If the alkylating agent can provide multiple alkyl groups, such as a diorganozinc compound where each zinc atom can provide two alkyl groups, the stoichiometry of the alkylating agent is adjusted accordingly to provide about one alkyl group for each Sn. Thus, for the diorganozinc compound, about one mole of Zn is required for every two moles of Sn. The amount of alkylating agent can be about ±25%, about ±20%, or about ±15% relative to the stoichiometry of the reagent, or in other words, the stoichiometry of the reagent + the amount selected or the stoichiometry of the reagent - the amount selected to achieve the desired process performance. One of ordinary skill in the art will recognize that additional ranges of relative amounts of the alkylating agent within the explicit ranges above are contemplated and are within the scope of the present disclosure.

Examples 2 and 3 use approximately stoichiometric amounts of alkylating agent, while Examples 1 and 4 use approximately 110% (or 100%+10%) of alkylating agent. The alkylating agent dissolved in an organic solvent can be gradually added to the reactor, such as dropwise or flowing at a suitable rate to control the reaction. The addition rate can be adjusted to control the course of the reaction, such as over a period of about 1 minute to about 2 hours, and in further embodiments, over a period of about 10 minutes to about 90 minutes. Taking into account the addition rate, the concentration of the alkylating agent can be adjusted within a reasonable value in the added solution. In principle, the alkylating agent can be started in the reactor with the gradual addition of tin tetramine. One of ordinary skill in the art will recognize that other ranges of alkylating agents and times of addition within the explicit ranges above are contemplated and within the scope of the present disclosure.

The reaction of introducing alkyl ligands into tin atoms can be carried out in a low oxygen, substantially oxygen-free, or oxygen-free environment, and an active inert gas flush can provide a suitable atmosphere, such as an anhydrous nitrogen flush or an argon flush. The following additives have been observed to reduce the addition of dialkyl groups to tin: pyridine, 2,6-lutidine, 2,4-lutidine, 4-dimethylaminopyridine, 2-dimethylaminopyridine, triphenylphosphine, tributylphosphine, trimethylphosphine, 1,2-dimethoxyethane, 1,4-dioxane, and 1,3-dioxane. Other neutral coordinating bases can work in the same manner. The reaction can optionally also contain about 0.25 to about 4 moles of neutral coordinating base per mole of tin. The reaction can be shielded from light during the reaction. The reaction can be carried out in an organic solvent, such as an alkane (such as pentane or hexane), an aromatic hydrocarbon (such as toluene), an ether (such as diethyl ether, C ₂ H ₅ OC ₂ H ₅ ), or a mixture thereof. The solvent can be anhydrous to avoid reaction with water. The reaction is generally carried out for about 15 minutes to about 24 hours, for about 30 minutes to about 18 hours in further embodiments, and for about 45 minutes to about 15 hours in other embodiments. The temperature during the reaction can be between about -100°C and about 100°C, in other embodiments, between about -75°C and about 75°C, and in other embodiments, between about -60°C and about 60°C. The reaction temperature may be controlled within the desired range by cooling or heating, and controlling the rate of reactant addition may also be used to affect temperature changes during the reaction. The monoalkyltintriamine product is typically an oil that can be purified using vacuum distillation. Typical yields of about 50% to 85% have been observed. Those of ordinary skill in the art will recognize that other concentration ranges and process conditions within the above-specified ranges are contemplated and within the scope of the present disclosure.

The alkylating agent can be a Grignard reagent, a diorganic zinc reagent or a monoorganic zinc amine. The Grignard reagent can be an organic magnesium halide. Specifically, the Grignard reagent in the reaction can be RMgX, wherein X is a halogen, typically Cl, Br or I. R can be an alkyl or cycloalkyl group and has 1 to 31 carbon atoms, and typically R can be more fully described as above with respect to the R portion of the product composition, which is incorporated into this paragraph discussion as a whole. For example, an alkyl or cycloalkyl group can be branched, can contain an aromatic group and/or can have one or more heteroatom functional groups containing atoms such as O, N, Si and/or halogens. Grignard reagents can be commercially available or can be synthesized using known methods. Commercial sources include American Elements Company, Sigma-Aldrich, and many other suppliers.

In some embodiments, the alkylating agent is a diorganic zinc reagent. The diorganic zinc reagent can provide two alkyl groups to the tin, so the amount of the diorganic zinc reagent can be adjusted according to the difference in molar equivalents. Specifically, the diorganic zinc reagent can be _R2Zn . R can be an alkyl or cycloalkyl group having 1 to 31 carbon atoms. The R group can be more fully described as described above with respect to the R portion of the product composition, and the above discussion of the R group associated with the monoalkyltin compound product is considered to be part of the discussion in this paragraph, as if it is reproduced here. For example, the alkyl or cycloalkyl group can be branched and can have one or more heteroatom functional groups containing atoms such as O, N, Si and/or halogens. Bicycloheptylzinc ((C ₇ H ₁₃ ) ₂ Zn) reactants are exemplified below. Bisorganic zinc compounds are commercially available or can be synthesized using known techniques. Commercial sources include, for example, Alfa Aesar, Sigma-Aldrich, Rieke Metals (Nebraska, USA), and Triveni Chemicals (India). The reactants used in the examples were synthesized.

In further embodiments, the alkylating agent is a monoorganic zinc amine ( _RZnNR'2 ). R can be an alkyl or cycloalkyl group typically having 1 to 30 carbon atoms. The R group can be more fully described as described above with respect to the R portion of the product composition, and the above discussion of the R group associated with the monoalkyltin compound product is considered part of the discussion in this paragraph, as if reproduced here. For example, the alkyl or cycloalkyl group can be branched and can have one or more carbon atoms, which are substituted with one or more heteroatom functional groups containing atoms such as O, N, Si and/or halogens. In some embodiments, R' is an alkyl or cycloalkyl group, which can be substituted with heteroatoms. In some embodiments, R' can have 1 to 8 carbon atoms, in some embodiments, 1 to 5 carbon atoms, and in other embodiments, 1 to 3 carbon atoms. R' can be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl or tertiary pentyl. Monoorganic zinc amines can be synthesized, for example, from alkyl zinc halides (RZnX, X = I, Br, Cl) and lithium amides (LiNR' ₂ ), which are commercial reagents from Sigma-Aldrich.

Monoalkyltintriamine prepared using the above method or other methods not explicitly described herein can be further purified using distillation. In order to reduce the temperature of the distillation process, the pressure can be reduced to, for example, a pressure of about 0.01 Torr to about 10 Torr, in a further embodiment, the pressure is about 0.05 Torr to about 5 Torr, and in a further embodiment, it is about 0.1 Torr to about 2 Torr. Suitable distillation columns with a volume suitable for the method can be used and are commercially available. The temperature can be controlled in the container of the material to be purified and along the column to achieve the desired separation. The thermal conditions of one embodiment are shown in Example 8 below, and based on the teachings of this article, these conditions can be easily and widely used for other compositions. If the dialkyltintriamine contaminant has a higher boiling point than the monoalkyltintriamine, the monoalkyltintriamine can be separated during the distillation process. During the distillation stage, the distillate can be taken out with a large amount of liquid removed, but Example 8 shows a good separation with reasonable yields and no detectable contaminants. If the dialkyltintriamine contaminant has a lower boiling point than the monoalkyltintriamine, the dialkyltintriamine can be separated by collecting and discarding the initial distillate during the distillation process.

Monoalkyltin trialkoxides can be prepared by reacting the corresponding monoalkyltin triamine with an alcohol in a non-aqueous solvent and a base. Using the methods described herein, low polyalkyltin contaminants in the monoalkyltin triamine can be brought into the monoalkyltin trialkoxide product so that the monoalkyltin trialkoxide product has low dialkyltin contaminants substantially at the above molar percentage. Suitable organic solvents include, for example, alkanes (such as pentane or hexane), aromatic hydrocarbons (such as toluene), ethers (such as diethyl ether, C ₂ H ₅ OC ₂ H ₅ ), or mixtures thereof. Alcohol is selected to provide the required alkoxy group so that the alcohol ROH introduces the -OR group as a ligand connected to the tin. Suitable R groups are provided above and are correspondingly related to the alcohol. Examples are provided below using triamyl alcohol, but other alcohols can be similarly used to provide the required -OR alkoxy ligands. The alcohol may be provided in approximately stoichiometric amounts. Since the alcohol is used to replace three amine groups, three molar equivalents of alcohol are a stoichiometric amount. Typically, the amount of alcohol may be at least about -5% stoichiometric equivalents, and in further embodiments, at least about stoichiometric equivalents, and an excess of alcohol may be used. Example 5 was performed using +3.33% stoichiometric equivalents of alcohol, i.e., 3.1 moles of alcohol per mole of monoalkyltintriamine.

To promote the purification of the alkyl tin trialkoxide product, a tetradentate chelating agent may be added to coordinate with the unreacted tin tetraamine species to form a complex that does not evaporate during distillation. For example, TREN, trien or other tetradentate non-planar coordination ligands may be used to complex with the unreacted species to promote purification. The ligand may be added at a selected time from the start of the reaction to any time before distillation is performed, in an amount of about 0.5 mol% to about 15 mol%, and in further embodiments, in an amount of about 1.0 mol% to about 10 mol% relative to the molar amount of tin. It has also been found that tetradentate non-planar ligands (such as TREN) can also effectively complex with tin tetraalkoxide and inhibit its distillation. Generally, it is desirable to have at least about a stoichiometric amount of tetradentate chelating agent per tin tetramine to inhibit distillation. Thus, for a given amount of tin tetramine, the amount of tetravalent chelating agent may be about 1:1 (molar), or at least about 95 mole % of tetravalent chelating agent may be used per mole of tin tetramine in some embodiments, about 98 mole % to about 200 mole % of tetravalent chelating agent may be used in other embodiments, and about 99 mole % to about 120 mole % of tetravalent chelating agent may be used in other embodiments. Thus, tetradentate non-planar ligands are effective in improving the purification of monoalkyltin trialkoxides from tin tetramine or tin tetraalkoxides. Those of ordinary skill in the art will recognize that ranges of additional reactant amounts within the above explicit ranges are contemplated and within the present disclosure. If desired, distillation may be performed to further purify the monoalkyltin trialkoxide from the polyalkyl contaminants.

Although monoalkyltin triamines with low polyalkyl contaminants can be effectively used to form derivatives with correspondingly low polyalkyl contaminants, the synthesis of monoalkyltin triamides from monoalkyltin triamines can be used to form low contaminant products even if the monoalkyltin triamines do not have low levels of contaminants, since the formation of crystals of monoalkyltin triamides can apparently exclude polyalkyl contaminants. Thus, the synthesis of monoalkyltin triamides provides a supplemental or alternative route to form compositions with low dialkyltin contaminants. Thus, in some embodiments, monoalkyltin triamines with higher than desired contaminants, such as from commercial sources or reaction routes with higher contaminant levels, can be used, yet still yield product compositions with low dialkyltin contaminants. Monoalkyltin triamides can be used to form monoalkyltin trialkoxide compositions with low dialkyltin contaminants.

The reaction is concerned with the addition of an N-alkylamide, such as N-methylacetamide (CH ₃ CONHCH ₃ ), to a monoalkyltintriamine. In general, the N-alkylamide reactant can be written ^{as RaCONHRb} , where ^Ra and ^Rb are each independently a alkyl group having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, etc. The crystal structure of the product compound has been determined and is shown in the following examples. In summary, the amide group in the product combines with the tin on the nitrogen atom to form a corresponding coordination structure.

In order to control the heat generation and the reaction process, the N-alkylamide reactant can be added gradually, for example, for at least about 2 minutes. The monoalkyltin triamine can be dissolved in an organic solvent at a concentration of about 0.1M to about 8M, and in a further embodiment, at a concentration of about 0.2M to about 6M. Suitable organic solvents include, for example, alkanes (such as pentane or hexane), aromatic hydrocarbons (such as toluene), ethers (such as diethyl ether, C ₂ H ₅ OC ₂ H ₅ ), or mixtures thereof. The reaction is exothermic and generally does not require heating. The reaction product can form crystals, and the reaction can generally last for about 20 minutes to 24 hours. After the reaction is complete, the solvent can be removed to collect the crystals of the product. The crystals can be washed and dried. It is observed that the dialkyltin compound is excluded from the product crystals. One of ordinary skill in the art will recognize that other ranges of reactant concentrations, addition times, and reaction times within the explicit ranges above are contemplated and within the scope of the present disclosure.

For processing of radiation-sensitive photoresist compositions, it may be necessary to react the monoalkyltriamidotin to form a monoalkyltin trialkoxide. Alkali metal alkoxides may be used to replace the triamido ligands with alkoxy ligands by reaction in an organic slurry. When the monoalkyltin trialkoxide is formed, it is dissolved in an organic solvent at a concentration of about 0.01 M to 2 M, in further embodiments, at a concentration of about 0.04 M to about 1 M, and in other embodiments, at a concentration of about 0.005 M to about 0.5 M. Alkali metal alkoxides can be written as ZOR', where Z is an alkali metal atom, such as K, Na or Li, and -OR' is an alkoxy group providing the corresponding R' group of the product composition for RSn(OR') _3. Some alkali metal alkoxides are commercially available, for example, from Sigma-Aldrich, and these compounds are highly hygroscopic, so they can be separated from air. Suitable organic solvents include, for example, alkanes (such as pentane or hexane), aromatic hydrocarbons (such as toluene), ethers (such as diethyl ether, C ₂ H ₅ OC ₂ H ₅ ), or mixtures thereof. The alkali metal alkoxide can be provided in at least a stoichiometric amount, which corresponds to three alkoxy groups per tin atom. The reaction can be carried out for about 15 minutes to about 48 hours. The product liquid may be distilled to purify the product. One of ordinary skill in the art will recognize that additional concentrations and time ranges within the above explicit ranges are contemplated and within the scope of the present disclosure.

Embodiment

Example 1: Synthesis of t-BuSn(NMe ₂ ) ₃

This example relates to the synthesis of a tin compound by replacing the N-methylamine group with a tertiary butyl group bonded to tin.

Sn(NMe ₂ ) ₄ (827.5 g, 2805 mmol, Sigma) was charged into a 5-liter three-necked round-bottom flask in an argon-filled glove box. Anhydrous ether (2000 ml) was added to the flask. A certain amount of t-BuMgCl (1500 ml, 2.06 M (freshly titrated), 3090 mmol) was added to another 2-liter two-necked round-bottom flask. The flask was stoppered and connected to a Schlenk line. The Sn(NMe ₂ ) ₄ solution was transferred to a 5-liter jacketed reactor and stirred at 240 RPM. The t-BuMgCl solution was delivered to a 5-liter jacketed reactor at a rate of 50 ml min ^-1 using an automatic syringe pump. The temperature of the mixture in the jacketed reactor was maintained at 20 °C. After complete addition of the t-BuMgCl solution, the reaction was stirred overnight. The resulting mixture was transferred to a 5-liter three-necked round-bottom flask equipped with a stirring bar through a 10-liter filter reactor. The solids in the 5-liter jacketed reactor and the filter reactor were washed with pentane (2 x 1 liter). The washings were collected in a 5-liter three-necked round-bottom flask equipped with a stirring bar and the volatiles were removed under vacuum. After removal of the volatiles, a light yellow oily suspension corresponding to the crude product was observed. The flask was placed in a glove box and the crude product was filtered through a coarse porosity fritted funnel. The filtrate was transferred to a 2-L two-necked round bottom flask equipped with a stir bar, stoppered and transferred to a Schlenk line. The crude product was purified by short-path vacuum distillation into a 1-L receiving flask (500 mTorr, 65°C to 75°C) to give 323 to 604 g, 37 to 70% of a colorless oil judged to be t-BuSn( _NMe2 ) ₃ . Proton NMR (Figure 1) and ¹¹⁹ Sn NMR (Figure 2) were performed, and the product had the following spectral peaks: ¹ H NMR (C ₆ D ₆ , MHz): 2.84 (s, 18H, -NCH 3 ), 1.24 (s, 9H, H ₃ CC-); ¹¹⁹ Sn NMR (C _{6 D 6 ,} 186.4 MHz: -85.69. Quantitative proton NMR and tin NMR were performed to evaluate the purity of the product based on standards. qNMR: ¹ H, 1,3,5-trimethoxybenzene standard, purity 94.5 (3) mol% (94.5±0.3 mol%) monoalkyltin; ¹¹⁹ Sn, MeSnPh ₃ standard, purity 93.5 (2) mol% monoalkyltin. ¹¹⁹ Sn qNMR of trace impurities: Impurities I _Impurities / I _{t-BuSn(NMe2)3} % Impurities / tBuSn(NMe ₂ ) ₃ (mol /mol ) tBu ₂ Sn(NMe ₂ ) ₂ 2.2 x ^10-2 2.6(1) Sn(NMe ₂ ) ₄ 3 x 10 ^-3 0.1(1)* *Value calculated by extrapolation of the calibration curve

Example 2: Synthesis of CySn(NMe ₂ ) ₃ (Cy = cyclohexyl)

This example is about the synthesis of tin compounds having a cyclohexyl group by using a Zn reagent instead of the N-methylamine group of Sn(NMe ₂ ) ₄ .

Sn(NMe ₂ ) ₄ (5.61 g, 19.0 mmol, Sigma) was charged into a 250 ml three-neck round bottom flask (RBF) in an argon-filled glove box. Anhydrous ether (150 ml) was added into the flask. In addition, LiNMe ₂ (0.97 g, 19.0 mmol, Sigma) and anhydrous ether (20 ml) were charged into a 100 ml RBF. CyZnBr (Cy = cyclohexyl, 48.5 ml, 0.392 M, 19.0 mmol, Sigma) was slowly added into the flask to produce CyZnNMe ₂ . Since it is an exothermic reaction, CyZnBr was slowly added to control the reaction temperature. The dropping funnel and reflux condenser were connected to a 250 ml three-neck RBF on a Schlenk line under active argon flushing. The CyZnNMe ₂ solution was added to the dropping funnel and distributed dropwise under stirring, while the 250 ml RBF was covered with aluminum foil to block light. After the addition was completed, the reaction was stirred overnight and the solvent was removed in vacuo to obtain a light orange oil with a precipitate. The oil was purified by vacuum distillation (58 to 62 ° C, 150 mTorr). The product obtained was 4.38 g (69% yield) of a colorless oil, which was judged to be CySn(NMe ₂ ) ₃ . Proton NMR (Figure 3) and ¹¹⁹ Sn NMR (Figure 4) were performed, and the product had the following spectral peaks: ¹ H NMR (C ₆ D ₆ , 500 MHz): 2.85 (s, 18H, -NCH 3 ), 1.86 (m, 3H, -Cy H ), 1.69 (m, 2H, -Cy H ₎ , 1.53 (m, 3H, -Cy H ), 1.24 (m, 3H, -Cy H ); ¹¹⁹ Sn NMR (C ₆ D ₆ , 186.4 MHz): -73.77.

Example 3: Synthesis of (CyHp)Sn(NMe ₂ ) ₃ (CyHp = cycloheptyl)

This example is about the synthesis of tintriamine with cycloheptyl group, as shown in the following formula. In this synthesis, the cycloheptyl group from the zinc reagent (CyHp) ₂ Zn replaces the N-methylamine group of Sn(NMe ₂ ) ₄ .

Sn(NMe ₂ ) ₄ (6.49 g, 22.0 mmol, Sigma) was charged into a 250 mL three-neck round bottom flask (RBF) in an argon filled glove box. Anhydrous ether (150 mL) was added. A dropping funnel and a reflux condenser were connected to the 250 mL three-neck RBF on a Schlenk line under active argon flushing. Separately prepared (CyHp) ₂ Zn (0.351 M, 31.3 mL, 11.0 mmol) was synthesized as follows: 2 CyHpMgBr + Zn(OCH ₃ ) ₂ . The (CyHp) ₂ Zn solution was added to the dropping funnel under active argon flushing and then dispensed dropwise under stirring while covering the 250 mL RBF with aluminum foil to block light. After the addition was complete, the reaction was stirred overnight. The solvent was then removed in vacuo. The reaction flask was placed in a glove box and hexanes were added. The solution was filtered through Celite ^® and the solvent was removed in vacuo to give a colorless oil with a precipitate. The oil was purified by vacuum distillation (82 to 86°C, 180 mTorr). The product obtained was 4.01 g (52% yield) of a colorless oil, identified as (CyHp)Sn(NMe ₂ ) ₃ . Proton NMR (Figure 5) and ¹¹⁹ Sn NMR (Figure 6) were performed, _and the product had the following spectral peaks observed: ¹ H NMR (C ₆ D ₆ , 500 MHz): 2.84 (s, 18H, -NCH 3 ), 2.01 (m, 2H, -CyHp H ), 1.82 (m, 1H, -CyHp H ), 1.69 – 1.23 (m, 10H, -CyHp H ); ¹¹⁹ Sn NMR (C ₆ D ₆ , 186.4 MHz): -66.93.

Example 4: Preparation of t-BuSn(NMe ₂ ) ₃ via added alkali

This example illustrates the synthesis of a tin composite by reacting a Grignard reagent with Sn(NMe ₂ ) ₄ in the presence of a base.

Sn(NMe ₂ ) ₄ (539.0 g, 1.827 mol, Sigma) was charged into a 5-liter three-neck RBF in an argon-filled glove box. About 3 liters of anhydrous diethyl ether and pyridine (289.1 g, 3.66 mol) were added to the flask. Two necks of the flask were plugged with glass stoppers, and a vacuum adapter was connected to the third neck. In addition, 1 liter of t-BuMgCl (Grenier reagent) was charged into a 2-liter two-neck RBF, and the t-BuMgCl was measured with a volumetric flask (2.01 M (titrated), 2.01 mol, Sigma). A 5-liter jacketed Chemglass ^™ reactor was prepared for high vacuum and thermal reactions on a Schlenk line filled with argon. The reactor was backfilled with argon and the jacket around the reaction vessel was cooled to -30°C.

Transfer the contents of the 5-liter three-neck RBF through polyethylene (PE) tubing to a Chemglass ^TM reactor under positive argon pressure. Start stirring with an overhead stirrer and cool the reaction temperature to -15°C. Add the Grignard reagent over a period of 20 to 30 minutes through polyethylene (PE) tubing on the Schlenk line with positive argon pressure while maintaining the internal reaction temperature below 5°C. Turns dark orange and precipitates. After the addition is complete, stir the reaction overnight to allow it to reach room temperature while keeping the reaction shielded from light with aluminum foil.

After reacting overnight, the reaction color was light yellow. The solvent was removed under vacuum by heating the jacket at 30 to 35 °C. After the solvent was removed, anhydrous pentane (~2.5 liters) was added to the reactor under positive argon pressure through a polyethylene tube and the solids were mixed thoroughly with an overhead stirrer. The reaction product dispersed in pentane was transferred to a 10-liter filter-type reactor with positive argon pressure through a polyethylene tube. The reaction product was filtered and then transferred to a 3-liter RBF through a polyethylene tube. The pentane solvent was removed under vacuum from the resulting light yellow filtrate to obtain a yellow oil. The oil was transferred to a 1 L Schlenk flask and vacuum distilled using a shortpath distillation head (50-52°C, 300 mTorr) to give 349.9 g (62%) of a colorless oil. Figures 7 ( ^1H NMR) and 8 ( ^119Sn NMR) are similar to Figures 1 and 2. Figures 1 and 2 show that the product consists of monoalkyl material in equilibrium with Sn( _NMe2 ) ₄ . Quantitative proton NMR and tin NMR were performed with selected standards to assess the purity of the product. qNMR: ¹ H, 1,3,5-trimethoxybenzene standard, purity 89.9 (7) mol% monoalkyltin; ¹¹⁹ Sn, MeSnPh ₃ standard, purity 93.6 (4) mol% monoalkyltin. ¹¹⁹ Sn qNMR of trace impurities: Impurities I _Impurities / I _{t-BuSn(NMe2)3} % Impurities / tBuSn(NMe ₂ ) ₃ (mol /mol ) tBu ₂ Sn(NMe ₂ ) ₂ 2 x 10 ^-3 0.1(1)* Sn(NMe ₂ ) ₄ 2.4 x ^10-2 2.3(1) *Value calculated by extrapolation of the calibration curve

Example 5: Preparation of high purity monoalkyl alkoxide t-BuSn(OtAm) ₃ from t-BuSn(NMe ₂ ) ₃

This example illustrates the synthesis of a monoalkyltin trialkoxide from the corresponding monoalkyltintriamine according to the following reaction.

In a glove box, a 2-liter two-necked RBF was charged with ~500 mL of pentane from Example 4 and t-BuSn(NMe ₂ ) ₃ (329.4 g, 1.07 mol). The flask was weighed on a balance and tris(2-aminoethyl)amine (3.91 g, 26.7 mmol) was added directly to the reaction mixture via syringe. Amine complexation and removal of stannous tetramine occurred during the reaction and purification. If stannous tetramine does not have to be removed from the system, the product of Example 1 can be used to synthesize additional monoalkyltin products. The reaction sequence can be continued with the material synthesized according to Example 1. A magnetic stir bar was added and the reaction was then sealed and sent to the Schlenk line. The flask was cooled in a dry ice/isopropanol bath. Separately, tert-amyl alcohol (2-methyl-2-butanol) (292.2 g, 3.315 mol) and a small amount of pentane were charged to a 1-liter Schlenk flask and connected to the Schlenk line. The alcohol/pentane solution in the Schlenk flask was transferred to the reaction flask via a cannula and outlet purged into a mineral oil bubbler connected in line to an acid trap solution of NMe ₂ H for off-gassed. After the addition of the alcohol was complete, the reaction was allowed to reach room temperature and stirred for 1 hour. After 1 hour of reaction, the solvent was removed in vacuo and the product was vacuum distilled (95 to 97°C, 500 mTorr) to give 435 g (93%) of a colorless oil. Figure 9 ( ¹ H NMR) and Figure 10 ( ¹¹⁹ Sn NMR) show that the NMR spectra of the final product t-BuSn(Ot-Am) ₃ have the following peaks: ¹ H NMR (C ₆ D ₆ , 500 MHz): 1.61 (m, 6H, -OC(CH ₃ ) ₂ CH ₂ ), 1.37 (m, 18H, -OC(CH ₃ ) ₂ ), 1.28 (s, 9H, -C(CH ₃ ) ₃ ), 1.01 (m, 9H, -OC(CH ₃ ) ₂ CH ₂ CH ³ ); ¹¹⁹ Sn NMR (C ₆ D ₆ , 186.4 MHz): -240.70. Quantitative proton NMR was performed to evaluate the purity of the product. qNMR: ¹ H, 1,3,5-trimethoxybenzene standard, purity 97.7 (3)%; ¹¹⁹ Sn, MeSnPh ₃ standard, 99 (1) mol% monoalkyltin.

Example 6: Preparation of tertiary butyl tris(N-methylacetamido)tin(IV)

This example illustrates the synthesis of a monoalkyl triamide tin composition by the reaction of t-BuSn(NMe ₂ ) ₃ with N-methylacetamide.

In a glove box, t-BuSn(NMe ₂ ) ₃ (40.13 g, 130 mmol) containing 1% t-Bu ₂ Sn(NMe ₂ ) ₂ was charged into a 250 mL Schlenk round bottom flask. t-BuSn(NMe ₂ ) ₃ was synthesized by Example 1 or Example 4. 50 mL of toluene was added to the round bottom flask, and then N-methylacetamide (28.6 g, 391 mmol, Sigma) was slowly added to control heat generation. An additional 30 mL of toluene was used to wash all the N-methylacetamide into the reaction flask. The flask was sealed with a ground glass stopper and transferred to the Schlenk line. Over a period of several hours, large crystals precipitated from the solution. Toluene was removed by cannula under active argon flushing. White crystals were obtained and were rinsed twice with 100 ml of pentane using a cannula and then removed. They were dried in vacuo to obtain 40.6 g (80%) of tert-butyltri(N-methylacetamido)tin(IV). FIG. 11 shows the crystal structure of the solid determined by X-ray diffraction. As shown in FIG. 12 , the proton NMR spectrum produced the following peaks: ¹ H NMR (C ₆ D ₆ , 500 MHz): 2.52 (s, 9H, -NCH ₃ ), 2.01 (m, 2H, -CyHp H ), 1.74 (s, 9H, -( H ₃ C) ₃ CSn) , 1.69 (s, 9H, -C H ₃ CO). As shown in FIG. 13 , the NMR spectrum of tin produces the following spectral peaks: ¹¹⁹ Sn NMR (C ₆ D ₆ , 186.4 MHz): -346.5.

Example 7: Synthesis of t-BuSn(Ot-Am) ₃

This example illustrates the synthesis of t-BuSn(Ot-Am) ₃ from the tertiary butyltri(N-methylacetamido)tin(IV) product of Example 6.

In a glove box with an argon atmosphere, tertiary butyl tris(N-methylacetamido)tin(IV) (100 g, 255 mmol) from Example 6 was charged into a 3-liter round bottom flask, and then NaOtAm (98 g, 890 mmol, Sigma) was added. The mixture was slurried in 1.5 liters of pentane using a magnetic stirrer and a 2.5-inch long egg-shaped stirring bar. The slurry thickened and turned milky white after 30 to 60 minutes. Stirring was continued for about 16 hours. The slurry was then filtered through a medium-pore glass funnel in the glove box, and the recovered solid was washed twice with 100 ml of pentane. The retained solids form very fine filter cakes during filtration, so occasional agitation is used to facilitate collection.

The filtrate was transferred to a double-necked 2-liter flask equipped with a stir bar, and then the flask was sealed with a ground glass stopper and a Schlenk-inlet adapter. The flask was taken out of the glove box and connected to the vacuum line in the fume hood, and the excess solvent was removed under vacuum. The crude product was then purified by vacuum distillation and collected in a 100-mL Schlenk storage bottle. For the vacuum distillation, the oil bath was set to 150°C. The product was distilled at 300 mTorr and a temperature of 98 to 102°C to obtain 74 g (66%) of the product. As shown in Figure 14, the proton NMR spectrum shows the following shifts: ¹ H NMR shift [400 MHz, C ₆ D ₆ ]: 1.64 (q, 6H, -CH ₂ ), 1.39 (s, 18H, -C(CH ₃ ) ₂ ), 1.29 (s, 9H, (CH ₃ ) ₃ CSn), 1.03 (t, 9H, -CCH ₃ ). As shown in Figure 15, the ¹¹⁹ Sn NMR spectrum shows the following peaks: ¹¹⁹ Sn NMR shift [149.18 MHz, C ₆ D ₆ ]: -241.9. Quantitative NMR was performed to evaluate the purity of the standard after evaluation. ¹ H qNMR, 1,3,5-trimethoxybenzene standard, purity 97.3 (1) mol% monoalkyl. ¹¹⁹ Sn qNMR of trace impurities: Impurities I _Impurities / I _{t-BuSn(OtAm)3} % Impurities / tBuSn (OtAm) ₃ (mol /mol ) tBu ₂ Sn(OtAm) ₂ 2 x 10 ^-3 0.1(2) Sn(OtAm) ₄ (Not observed) 0.0(3)

Example 8: Distillation and purification

This example demonstrates the effectiveness of fractionating and purifying t-BuSn ₍ NMe ₂ ) ₃ by separating a mixture of t-Bu ₂ Sn(NMe 2 ) ₂ and t-BuSn(NMe ₂ ) ₃ .

In a glove box, t-BuSn(NMe ₂ ) ₃ containing ~3.27% t-Bu ₂ Sn(NMe ₂ ) ₂ (1420 g total, 4.6 mol) was charged to a 3000 mL three-neck round bottom flask (RBF); the sample was prepared by the method described in Example 1 using a modified t-BuMgCl:Sn(NMe ₂ ) ₄ ratio. Glass stoppers were placed in two necks of the RBF and the third neck was connected to a Schlenk line. In addition, a 5-liter Chemglass jacketed reactor was equipped with an overhead stirrer, temperature probe, and two 18-inch distillation columns, stacked one on top of the other. The distillation column was filled with Pro-Pak ^TM (ThermoScientific, 0.24 square inches) high efficiency distillation column packing. A short-path distillation joint with a temperature probe was connected to the top of the distillation tube. The top of the short-path joint was then connected to a 3-arm cow joint equipped with three 500 ml Schlenk bombs. The reactor was evacuated and backfilled with argon three times. The mixture rich in t-Bu ₂ was added to the reactor through a large sleeve under argon. The jacketed reactor was heated to between 110 and 120°C under reduced pressure (500 mTorr) to initiate distillation. The temperature at the bottom of the distillation column was measured to be 95 to 100°C, while the temperature at the top of the column was maintained between 58 and 60°C. Three fractions were collected and each fraction was analyzed by ¹¹⁹ Sn NMR spectroscopy. Figures 16 to 19 are ¹¹⁹ Sn NMR spectra of the combined sample (Figure 16) and ¹¹⁹ Sn NMR spectra of each of the three fractions (shown in Figures 17 to 19, respectively). None of the three fractions showed NMR signals for t-Bu ₂ Sn(NMe ₂ ) _2. The total yield of all fractions combined was 850 g (60%). ¹¹⁹ Sn NMR (C ₆ D ₆ , 186.4 MHz): -85.45.

Example 9: Vacuum distillation purification

This example demonstrates the effectiveness of using vacuum distillation to purify t-BuSn(OtAm) ₃ to prepare an amine-free composition, as demonstrated by separation from a mixture of Sn(OtAm) ₄ and t-BuSn(OtAm) _3. Tris(2-aminoethyl)amine (TREN) was used as a purification aid.

In a glove box with an argon atmosphere, t-BuSn(OtAm) ₃ [25 g, 55.825 mmol] contaminated with about 1.3% Sn(OtAm) ₄ was charged into a 100 mL round-bottom Schlenk flask and 10 mL of anhydrous pentane was added. The mixture was stirred with a magnetic stirrer before TREN [0.112 g, 0.7686 mmol] was added using a glass pipette. The flask was sealed using a glass stopper for a 24/40 ST joint and a Teflon valve for the sidearm port. The flask was connected to a Schlenk line and placed under inert gas (nitrogen) and placed in a silicone oil bath. Agitation and heating control were achieved using a Heidolph HEI-TEC stirring plate with a Pt/1000 temperature probe to achieve feedback temperature control of the oil bath. The oil bath was maintained at 45°C and excess solvent was then removed under vacuum. After verifying solvent removal using a millitorr vacuum gauge, a short-path vacuum distillation apparatus was set up using a 50 ml Schlenk bottle as a receiving vessel. Vacuum distillation was performed at 300 mTorr absolute pressure, bath temperature 150°C, and vapor temperature 94 to 98°C.

Assuming 100% removal of Sn(O ^t Am) ₄ , the theoretical recovery is 24.66 g, and the recovered distillate is 21.70 g, with a recovery of 88%. The ¹¹⁹ Sn NMR spectra are shown in Figure 20 (baseline) and Figure 21 (purified). ¹¹⁹ Sn NMR shift [149.18 MHz, C ₆ D ₆ ]: ^t Bu ₂ Sn(O ^t Am) ₂ : -113 ppm; ^t BuSn(O ^t Am) ₃ : -241 ppm; Sn(O ^t Am) ₄ : -370 ppm.

This application is a continuation-in-part of co-pending U.S. patent application 15/950,292 filed on April 11, 2018 by Edson et al., entitled “Monoalkyl Tin Compounds With Low Polyalkyl Contamination, Their Compositions and Methods,” and a continuation-in-part of co-pending U.S. patent application 15/950,286 filed on April 11, 2018 by Edson et al., entitled “Monoalkyl Tin Compounds With Low Polyalkyl Contamination, Their Compositions and Methods,” the entire texts of which are incorporated herein by reference.

The above embodiments are illustrative and not restrictive. Other embodiments are within the scope of the application. In addition, although the present invention has been described with reference to specific embodiments, those skilled in the art will recognize that modifications can be made in form and detail without departing from the spirit and scope of the present invention. The arbitrary incorporation of the above-mentioned references is limited and does not include the subject matter that is contrary to the explicit disclosure herein. With respect to the scope of the specific structures, compositions, and/or methods of the components, elements, ingredients, or other parts described herein, unless otherwise specifically indicated, it should be understood that the disclosure herein covers specific embodiments, embodiments including specific components, elements, ingredients, other parts, or combinations thereof, and embodiments including other features that do not change the basic nature of the subject matter disclosed herein and that are substantially composed of specific components, ingredients, other parts, or combinations thereof.

without

Figure 1 is the ¹ H NMR spectrum of t-BuSn(NMe ₂ ) ₃ synthesized using Grignard reagent. Figure 2 is the ^{119 Sn NMR spectrum of t-BuSn(NMe 2 ) 3 used to obtain the spectrum of Figure 1. Figure 3 is the 1 H NMR spectrum of CySn(NMe 2 ) 3 (Cy=cyclohexyl) synthesized using alkyl zinc halide reagent. Figure 4 is the 119} _{Sn NMR} ^spectrum _{of CySn} ⁽ NMe ₂ ) ₃ used to obtain the spectrum of Figure 3. Figure 5 is the ¹ H NMR spectrum of CyHpSn(NMe ₂ ) ₃ synthesized using dialkyl zinc reagent. FIG. 6 is a ¹¹⁹ Sn NMR spectrum of CyHpSn(NMe ₂ ) ₃ correspondingly used to obtain the spectrum of FIG. 5. FIG. 7 is a ¹ H NMR spectrum of t-BuSn(NMe ₂ ) ₃ synthesized using a Grignard reagent and a neutral base. FIG. 8 is a ¹¹⁹ Sn NMR spectrum of t-BuSn(NMe ₂ ) ₃ correspondingly used to obtain the spectrum of FIG. 7. FIG. 9 is a ¹ H NMR spectrum of t-BuSn(Ot-Am) ₃ synthesized from t-BuSn(NMe ₂ ) 3. FIG. ₁₀ is a ¹¹⁹ Sn NMR spectrum of t-BuSn(Ot-Am) ₃ correspondingly used to obtain the spectrum of FIG. 9. Figure 11 shows the structure of t-butyltris(N-methylacetamido)tin(IV) obtained by X-ray structure determination of the crystallized product. Figure 12 shows the 1 H NMR spectrum of t-butyltris(N-methylacetamido)tin(IV). Figure 13 shows the ¹¹⁹ Sn NMR spectrum of t-butyltris(N-methylacetamido)tin(IV). Figure 14 shows the ¹ H NMR spectrum of t-BuSn(Ot-Am) ₃ synthesized from t-butyltris(N-methylacetamido)tin(IV). Figure 15 shows the ¹¹⁹ Sn NMR spectrum of t-BuSn(Ot-Am) ₃ synthesized from t-butyltris(N ^- methylacetamido)tin(IV). FIG. 16 is a ¹¹⁹ Sn NMR spectrum of t-BuSn(NMe ₂ ) ₃ doped with t-Bu ₂ Sn(NMe ₂ ) _2. The signal at 85.48 ppm corresponds to t-BuSn(NMe ₂ ) ₃ and the signal at 56.07 ppm corresponds to t-Bu ₂ Sn(NMe ₂ ) _2. FIG. 17 is a ¹¹⁹ Sn NMR spectrum of t-BuSn(NMe ₂ ) ₃ of the first fraction collected by fractionation of the sample of FIG. 16. FIG. 18 is a ¹¹⁹ Sn NMR spectrum of t-BuSn(NMe ₂ ) ₃ of the second fraction collected by fractionation of the sample of FIG. 16. Figure 19 is the ¹¹⁹ Sn NMR spectrum of t-BuSn(NMe ₂ ) ₃ from the third distillation fraction collected by distillation of the sample in Figure 16. Figure 20 is the 119 Sn NMR spectrum of baseline tBuSn(O ^t Am) _3. Figure 21 is the ¹¹⁹ Sn NMR spectrum of tBuSn(O ^t Am) ₃ after adding tris(2-aminoethyl) ^amine (TREN) and then distilling.

Claims (24)

A high purity liquid composition comprises: a monoalkyl tin triamide compound represented by the chemical formula RSn(NR' ₂ ) ₃ , wherein R comprises a alkyl group containing 1 to 31 carbon atoms, wherein one or more carbon atoms are optionally substituted by one or more heteroatom functional groups; wherein R' is a alkyl group having 1 to 10 carbon atoms; and wherein the composition is prepared by the following method, the method comprising: reacting a tin tetraamine represented by the formula Sn(NR' ₂ ) ₄ with an alkylating agent, wherein the amount of the alkylating agent is within ±25% of the stoichiometric amount of the tin tetraamine to form a product composition with low polyalkyl tin contamination. The composition as described in claim 1, wherein the one or more heteroatom functional groups contain O, N, Si, and/or halogen atoms. The composition as described in claim 1, wherein R is represented by R ¹ R ² R ³ C-, wherein R ¹ and R ² are each independently an alkyl group having 1 to 10 carbon atoms, and R ³ is hydrogen or an alkyl group having 1 to 10 carbon atoms. The composition of claim 1, wherein R comprises methyl, ethyl, isopropyl, tertiary butyl, tertiary pentyl, di-butyl, neopentyl, cycloheptyl, cyclohexyl, cyclopentyl, cyclobutyl, or cyclopropyl. The composition as described in claim 1, wherein R comprises a tertiary butyl group. The composition of claim 1, wherein R is functionalized with a phenyl group or a cyano group. The composition as described in claim 1, wherein R comprises an aryl group or an alkenyl group. The composition of claim 1, wherein R' comprises a methyl group, an ethyl group, an isopropyl group, a tertiary butyl group, or a tertiary pentyl group. The composition as described in claim 1, wherein R' comprises a methyl group. The composition of claim 1, wherein R comprises methyl (CH ₃ -), ethyl (CH ₃ CH ₂ -), isopropyl (CH ₃ CH ₃ HC-), tertiary butyl ((CH ₃ ) ₃ C-), tertiary pentyl (CH ₃ CH ₂ (CH ₃ ) ₂ C-), dibutyl (CH ₃ (CH ₃ CH ₂ )CH-), neopentyl ((CH ₃ ) ₃ CCH ₂ -), cyclohexyl, cyclopentyl, cyclobutyl, or cyclopropyl, and wherein R' comprises methyl, ethyl, isopropyl, tertiary butyl, or tertiary pentyl. The composition of claim 1, wherein the monoalkyltintriamine comprises t-BuSn(NMe ₂ ) ₃ . The composition of claim 1, wherein the composition comprises a combination of alkyl ligands. The composition of claim 1, wherein the amount of the alkylating agent is within ±15% of the stoichiometric amount of the tintetramine. The composition of claim 1, wherein the amount of the alkylating agent is +10% to +25% relative to the stoichiometric amount of the tintetramine. The composition of claim 1, wherein the method comprises fractionating after the reaction. The composition as claimed in claim 1, wherein the composition contains no more than 1 mol % of a polyalkyltin compound as an impurity relative to the total amount of tin. The composition as claimed in claim 1, wherein the composition contains no more than 0.5 mol% of a dialkyltin compound as an impurity relative to the total amount of tin. A use of the composition as claimed in claim 1, which is used to form a radiation patternable composition. A solution comprising the composition as described in any one of claims 1 to 17 and an organic solvent. The solution as described in claim 19 has a concentration of 0.005M to 0.5M, wherein the solvent comprises alcohol. A method for selectively forming a monoalkyltin trialkoxide with low polyalkyltin contaminants, the method comprising: reacting a composition as described in any one of claims 1 to 17 with an alcohol represented by the formula HOR" in an organic solvent to form RSn(OR") ₃ , wherein R" is each independently a alkyl group having 1 to 10 carbon atoms, thereby forming a product composition with low polyalkyltin contaminants. A method of forming a radiation-sensitive photoresist composition suitable for radiation patterning, the method comprising applying a composition as described in any one of claims 1 to 17 to form a radiation-patternable composition. The method of claim 22, wherein the coating comprises in situ hydrolysis of a pure alkyltin precursor composition. The method of claim 22 or 23, wherein the radiation-patternable composition comprises an oxo-hydroxo hydrolysis product.

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